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Date: Sat, 17 May 2008 06:21:18 -0700 From: "Pallipadi, Venkatesh" <venkatesh.pallipadi@...el.com> To: "Theodore Ts'o" <tytso@....edu>, <linux-kernel@...r.kernel.org> Cc: "Ingo Molnar" <mingo@...e.hu>, "Siddha, Suresh B" <suresh.b.siddha@...el.com> Subject: RE: REGRESSION: 2.6.26-rc2-git4: X server failed start on X61s laptop >-----Original Message----- >From: Theodore Ts'o [mailto:tytso@....edu] >Sent: Saturday, May 17, 2008 12:32 AM >To: linux-kernel@...r.kernel.org >Cc: Pallipadi, Venkatesh >Subject: REGRESSION: 2.6.26-rc2-git4: X server failed start on >X61s laptop > > >The X server failed to come up using the Intel driver, and forced a >fallback to the 800x600 VESA server. This was on my Lenovo X61s laptop >with an Intel chipset, running Ubuntu Gutsy. When it failed, >there were >a large number of these errors in the /var/log/messages: > >mtrr: type mismatch for e0760000,10000 old: write-back new: >write-combining >mtrr: type mismatch for e0740000,20000 old: write-back new: >write-combining >mtrr: type mismatch for e0700000,40000 old: write-back new: >write-combining >mtrr: type mismatch for e0600000,100000 old: write-back new: >write-combining >mtrr: type mismatch for e0400000,200000 old: write-back new: >write-combining >mtrr: type mismatch for e0000000,400000 old: write-back new: >write-combining > ... > >On kernels where this error did not occur during the bisect, >there would >still be one of these messages: > >mtrr: type mismatch for e0000000,10000000 old: write-back new: >write-combining > >... but the X server would correctly start. > >The git bisect identified this commit as the guilty one: > >1c12c4cf9411eb130b245fa8d0fbbaf989477c7b is first bad commit >commit 1c12c4cf9411eb130b245fa8d0fbbaf989477c7b >Author: Venki Pallipadi <venkatesh.pallipadi@...el.com> >Date: Wed May 14 16:05:51 2008 -0700 > > mprotect: prevent alteration of the PAT bits > > There is a defect in mprotect, which lets the user change >the page cache > type bits by-passing the kernel reserve_memtype and free_memtype > wrappers. Fix the problem by not letting mprotect change >the PAT bits. > Can you please send the complete dmesg after X failure, with patch here and debugpat boot option. http://www.ussg.iu.edu/hypermail/linux/kernel/0805.0/2657.html Thanks, Venki -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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